BSC 2010 EXAM QUESTIONS AND
ANSWERS ALL CORRECT
The major difference between a cell that responds to signal and one that does not is the
presence of a ______________. - Answer- receptor
Single-stranded RNA can fold in on itself, creating three-dimensional structures for the
bonding and recognition of other molecules. The folds are stabilized by
___________________. - Answer- hydrogen bonds
The LDL receptor is a transmembrane protein that crosses the plasma membrane, with
portions of the protein extending both outside of the cell and into the interior of the cell.
The amino acid side chains (R groups) in the region of the protein embedded in the
membrane are most likely? - Answer- Hydrophobic (R groups will be compatible to their
surroundings)
When a mouse cell and a human cell are fused, the membrane proteins of the two cells
become uniformly distributed over the surface of the hybrid cell. This occurs because... -
Answer- many proteins can move around within the bilayer
Type 2 diabetes, often associated with obesity, results in an increase in blood-glucose
levels. It occurs in humans as well as in animals, including domestic dogs and cats. One
early sign that a person or animal might be developing type 2 diabetes is excessive
thirst. Why? What is happening at the cellular level? - Answer- blood is hypertonic to
cells (cells lose water and we perceive this as thirst)
When placed in water, wilted plants "perk up" and lose their limpness because of... -
Answer- osmosis of water into the plant cells
Suppose the inside of a cell has a solute concentration of 4M. Which of the following
solutes outside of the cell would require active transport into the cell? - Answer- 3 M
Na+ (Na+ is charged and CO2 is non-polar)
A single bacterium divides into two bacteria that are identical to, but smaller than, the
original bacterium. Which characteristic of life does this best describe? - Answer-
replication of genetic material for reproduction
Why did the ancient evolution of photosynthesis in the ancient ocean allow organisms to
colonize land? - Answer- ozone formation created a habitable environment (with
oxygen, you get ozone formation)
, True or False, Organization (ex building molecules, constructing tissues) in life requires
energy - Answer- True
True or False, You hypothesize that increased light levels will enhance
growth of your houseplants. You test this hypothesis, moving the
plants to an area in your home with more light. Over several weeks,
and you find that the plants begins to look fuller and healthier . This
result proves your original hypothesis. - Answer- False, you don't prove a hypothesis is
true your findings support that hypothesis but there are many alternatives that can be
tested
An atom with _____ has an atomic number of 14 (atomic number refers to protons) -
Answer- so this atom also has 14 protons
What determines if a molecule is polar or non-polar? - Answer- the differences in the
electronegativities between the atoms (an atom's attraction for the electrons in a bond)
Small molecules containing several hydroxyl groups are typically... - Answer- Soluble in
water, used for hydrogen bonding with water leading to solubility
Which of these molecules contains only nonpolar bonds? - Answer- O2
An atom has an atomic number of 12. Assuming neutrality, how many valence electrons
does it have? - Answer- 2
Which factor defines whether a reaction is endergonic? - Answer- Delta G
During a typical hydrolysis reaction in cells, the energy required to break bonds in the
substrate is ______ the energy released when bonds are formed in the products. -
Answer- Less than (hydrolysis= exergonic)
Gibbs fres energy is negative for _______ reactions, which are typically associated with
a ________ change in enthalpy and a ________ change in entropy - Answer-
Exergonic, Negative, and Positive
True or False, Energy can be transformed during metabolic reactions. - Answer- True
True or False, For each reaction in a metabolic pathway, a small amount of energy
disappears due to the increase in entropy. - Answer- False (energy NEVER disappears
True or False, Endergonic and Exergonic reactions can both involve breaking of bonds.
- Answer- True, (Yes, bonds must be broken in the reactants regardless of whether the
reaction is exergonic or endergonic)
ANSWERS ALL CORRECT
The major difference between a cell that responds to signal and one that does not is the
presence of a ______________. - Answer- receptor
Single-stranded RNA can fold in on itself, creating three-dimensional structures for the
bonding and recognition of other molecules. The folds are stabilized by
___________________. - Answer- hydrogen bonds
The LDL receptor is a transmembrane protein that crosses the plasma membrane, with
portions of the protein extending both outside of the cell and into the interior of the cell.
The amino acid side chains (R groups) in the region of the protein embedded in the
membrane are most likely? - Answer- Hydrophobic (R groups will be compatible to their
surroundings)
When a mouse cell and a human cell are fused, the membrane proteins of the two cells
become uniformly distributed over the surface of the hybrid cell. This occurs because... -
Answer- many proteins can move around within the bilayer
Type 2 diabetes, often associated with obesity, results in an increase in blood-glucose
levels. It occurs in humans as well as in animals, including domestic dogs and cats. One
early sign that a person or animal might be developing type 2 diabetes is excessive
thirst. Why? What is happening at the cellular level? - Answer- blood is hypertonic to
cells (cells lose water and we perceive this as thirst)
When placed in water, wilted plants "perk up" and lose their limpness because of... -
Answer- osmosis of water into the plant cells
Suppose the inside of a cell has a solute concentration of 4M. Which of the following
solutes outside of the cell would require active transport into the cell? - Answer- 3 M
Na+ (Na+ is charged and CO2 is non-polar)
A single bacterium divides into two bacteria that are identical to, but smaller than, the
original bacterium. Which characteristic of life does this best describe? - Answer-
replication of genetic material for reproduction
Why did the ancient evolution of photosynthesis in the ancient ocean allow organisms to
colonize land? - Answer- ozone formation created a habitable environment (with
oxygen, you get ozone formation)
, True or False, Organization (ex building molecules, constructing tissues) in life requires
energy - Answer- True
True or False, You hypothesize that increased light levels will enhance
growth of your houseplants. You test this hypothesis, moving the
plants to an area in your home with more light. Over several weeks,
and you find that the plants begins to look fuller and healthier . This
result proves your original hypothesis. - Answer- False, you don't prove a hypothesis is
true your findings support that hypothesis but there are many alternatives that can be
tested
An atom with _____ has an atomic number of 14 (atomic number refers to protons) -
Answer- so this atom also has 14 protons
What determines if a molecule is polar or non-polar? - Answer- the differences in the
electronegativities between the atoms (an atom's attraction for the electrons in a bond)
Small molecules containing several hydroxyl groups are typically... - Answer- Soluble in
water, used for hydrogen bonding with water leading to solubility
Which of these molecules contains only nonpolar bonds? - Answer- O2
An atom has an atomic number of 12. Assuming neutrality, how many valence electrons
does it have? - Answer- 2
Which factor defines whether a reaction is endergonic? - Answer- Delta G
During a typical hydrolysis reaction in cells, the energy required to break bonds in the
substrate is ______ the energy released when bonds are formed in the products. -
Answer- Less than (hydrolysis= exergonic)
Gibbs fres energy is negative for _______ reactions, which are typically associated with
a ________ change in enthalpy and a ________ change in entropy - Answer-
Exergonic, Negative, and Positive
True or False, Energy can be transformed during metabolic reactions. - Answer- True
True or False, For each reaction in a metabolic pathway, a small amount of energy
disappears due to the increase in entropy. - Answer- False (energy NEVER disappears
True or False, Endergonic and Exergonic reactions can both involve breaking of bonds.
- Answer- True, (Yes, bonds must be broken in the reactants regardless of whether the
reaction is exergonic or endergonic)
